Will Monarch Caterpillars Eat More in the Light Than Those in the Dark?
Luke Salscheider and
Christine Johnson
8th Grade
St. Francis - St. James United School
St Paul, MN
Introduction
Our study group did its work feeding monarch caterpillars in the light and dark.
We wanted to determine whether monarch caterpillars would eat more in the light
than those in the dark. The data below will help you understand how we performed
the study.
Method
We began with 88 first and second instar caterpillars. We split them into two groups.
There were 48 caterpillars in the dark and 40 caterpillars in the light. We carefully
traced the milkweed leaves onto a piece of paper, on this paper were squares each
measuring 1 cm2. The reason we did this was to determine how much each
group ate. We recorded this information for a week and 4 days.
Results
Our figures are not perfectly accurate because we did not keep track of each caterpillar
separately, nor could we account for portions of leaves that dried up. In addition
to this, some of the larvae died. So, we counted the remainder of the caterpillars
and found we had 34 in the light and 25 in the dark left. We performed the experiment
by keeping track of how much milkweed the caterpillars in the light and in the dark
ate in cm2. After they were all in the pupa stage, we calculated how
much the caterpillars in the groups had eaten. The caterpillars in the light ate
a total of 4687 cm2 and the caterpillars in the dark ate a total of 4287
cm2. We then divided these numbers by the respective number of caterpillars
to get our final data.


This experiment was exciting but difficult. It took an amount of patience and work,
but it was worth it. Some of the data we have we were able to find because our group
worked well together. This was a very good experience for all of us and we learned
many things about monarch butterflies. We learned that they eat more milkweed than
we ever expected and their size does not affect their gender.
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